OR 241: Isthmus Slough, East Approach Bridge
Start Date: October 2010
End Date: June 2011
The Isthmus Slough project illustrates how Accelerated Bridge Construction (ABC) can provide a cost-effective solution to the problem faced by numerous communities across the country: failing infrastructure with inadequate funds for rebuilding using traditional methods.
Thanks to careful collaboration with owner/designer, Oregon Dept. of Transportation, Hamilton Construction was able to replace in record time the failing wood structure on the East approach to this bascule bridge—a key connector for commuters and commercial traffic in the Oregon Coastal town of Coos Bay. Using ABC techniques, the entire east approach was replaced during a demanding 13-day closure thereby minimizing impact to the public and avoiding the cost of a detour bridge or the disruption of a six month closure. Hamilton was able to accomplish this by building the entire substructure underneath the existing bridge, including driving more than 20 pilings with 36″ x 1″ dimensions in water with depths ranging from 90ft. to 120 ft. and a six ft. tidal variation.